Bottom Line:
IL-10 expression mediated by the HSV vectors resulted in a significant elevation of mechanical threshold.The area under the effect-time curves (AUC) in mechanical threshold in rats inoculated with the HSV vectors expressing IL-10, was increased compared with the control vectors, indicating antinociceptive effect of the IL-10 vectors.The blocking of the signaling of these proinflammatory molecules is able to reduce HIV-related neuropathic pain, which provide a novel mechanism-based approach to treating HIV-associated neuropathic pain using gene therapy.

Results: Neuropathic pain was induced by peripheral HIV coat protein gp120 combined with 2',3'-dideoxycytidine (ddC, one of the nucleoside reverse transcriptase inhibitors (NRTIs)). Mechanical threshold was tested using von Frey filament fibers. Non-replicating herpes simplex virus (HSV) vectors expressing interleukin 10 (IL10) were inoculated into the hindpaws of rats. The expression of TNFα, SDF1α, and CXCR4 in the lumbar spinal cord and L4/5 dorsal root ganglia (DRG) was examined using western blots. IL-10 expression mediated by the HSV vectors resulted in a significant elevation of mechanical threshold. The anti-allodynic effect of IL-10 expression mediated by the HSV vectors lasted more than 3 weeks. The area under the effect-time curves (AUC) in mechanical threshold in rats inoculated with the HSV vectors expressing IL-10, was increased compared with the control vectors, indicating antinociceptive effect of the IL-10 vectors. The HSV vectors expressing IL-10 also concomitantly reversed the upregulation of p-p38, TNFα, SDF1α, and CXCR4 induced by gp120 in the lumbar spinal dorsal horn and/or the DRG at 2 and/or 4 weeks.

Conclusion: The blocking of the signaling of these proinflammatory molecules is able to reduce HIV-related neuropathic pain, which provide a novel mechanism-based approach to treating HIV-associated neuropathic pain using gene therapy.

Figure 3: The effect of IL-10 mediated by the HSV vectors on the expression of TNFα in the DRG and the SDH at 2 or 4 weeks. Rats with neuropathic pain were inoculated with QHIL10 or Q0ZHG 1 week post gp120 with ddC. In the control group, rats received the sham surgery with saline IP injection and Q0ZHG (sham + sal + Q0ZHG). The data were analyzed using one way ANOVA with post hoc PLSD test, mean ± SEM. (A and B) Two weeks post vector injection, the L4/5 DRG (A) and the SDH (B) were harvested, and the expression of TNFα was tested using western blots. ** P < 0.01 vs. control, # P < 0.05, ## P < 0.01 vs gp120 + ddC + Q0ZHG, n = 4 rats. (C and D) Four weeks post vector injection, the L4/5 DRG (C) and the SDH (D) were harvested, and the expression of TNFα was tested using western blots. *P < 0.05 vs. control, # P < 0.05 vs gp120 + ddC + Q0ZHG, n = 4 rats.

Mentions:
Evidence shows that HIV gp120 or ddC mediated-neuropathic pain increases TNFα in the spinal cord and the DRG [4,14,30]. In the current study, we examined whether overexpression of IL10 mediated by the HSV vectors reduced TNFα in neuropathic pain induced by gp120 + ddC. The L4/5 DRG and the SDH were harvested for western blots for full-length membrane TNFα on 2 weeks post vector injection. The data were presented as mean ± SEM, and were compared using one way ANOVA with a post hoc PLSD test (StatView), n = 4 rats. In the DRG, there was a marked increase in TNFα in the gp120 + ddC + Q0ZHG group compared with that in the sham group (P < 0.01 vs sham + sal + Q0ZHG, Figure 3A); TNFα in the gp120 + ddC + QHIL10 group, was significantly lower than that in the gp120 + ddC + Q0ZHG group (P < 0.05, Figure 3A). In the SDH, there was a marked increase in TNFα in the gp120 + ddC + Q0ZHG group compared with that in the sham group (P < 0.01, Figure 3B); TNFα expression in the gp120 + ddC + QHIL10 group was significantly lower than that in the gp120 + ddC + Q0ZHG (P < 0.01, Figure 3B).

Figure 3: The effect of IL-10 mediated by the HSV vectors on the expression of TNFα in the DRG and the SDH at 2 or 4 weeks. Rats with neuropathic pain were inoculated with QHIL10 or Q0ZHG 1 week post gp120 with ddC. In the control group, rats received the sham surgery with saline IP injection and Q0ZHG (sham + sal + Q0ZHG). The data were analyzed using one way ANOVA with post hoc PLSD test, mean ± SEM. (A and B) Two weeks post vector injection, the L4/5 DRG (A) and the SDH (B) were harvested, and the expression of TNFα was tested using western blots. ** P < 0.01 vs. control, # P < 0.05, ## P < 0.01 vs gp120 + ddC + Q0ZHG, n = 4 rats. (C and D) Four weeks post vector injection, the L4/5 DRG (C) and the SDH (D) were harvested, and the expression of TNFα was tested using western blots. *P < 0.05 vs. control, # P < 0.05 vs gp120 + ddC + Q0ZHG, n = 4 rats.

Mentions:
Evidence shows that HIV gp120 or ddC mediated-neuropathic pain increases TNFα in the spinal cord and the DRG [4,14,30]. In the current study, we examined whether overexpression of IL10 mediated by the HSV vectors reduced TNFα in neuropathic pain induced by gp120 + ddC. The L4/5 DRG and the SDH were harvested for western blots for full-length membrane TNFα on 2 weeks post vector injection. The data were presented as mean ± SEM, and were compared using one way ANOVA with a post hoc PLSD test (StatView), n = 4 rats. In the DRG, there was a marked increase in TNFα in the gp120 + ddC + Q0ZHG group compared with that in the sham group (P < 0.01 vs sham + sal + Q0ZHG, Figure 3A); TNFα in the gp120 + ddC + QHIL10 group, was significantly lower than that in the gp120 + ddC + Q0ZHG group (P < 0.05, Figure 3A). In the SDH, there was a marked increase in TNFα in the gp120 + ddC + Q0ZHG group compared with that in the sham group (P < 0.01, Figure 3B); TNFα expression in the gp120 + ddC + QHIL10 group was significantly lower than that in the gp120 + ddC + Q0ZHG (P < 0.01, Figure 3B).

Bottom Line:
IL-10 expression mediated by the HSV vectors resulted in a significant elevation of mechanical threshold.The area under the effect-time curves (AUC) in mechanical threshold in rats inoculated with the HSV vectors expressing IL-10, was increased compared with the control vectors, indicating antinociceptive effect of the IL-10 vectors.The blocking of the signaling of these proinflammatory molecules is able to reduce HIV-related neuropathic pain, which provide a novel mechanism-based approach to treating HIV-associated neuropathic pain using gene therapy.

Results: Neuropathic pain was induced by peripheral HIV coat protein gp120 combined with 2',3'-dideoxycytidine (ddC, one of the nucleoside reverse transcriptase inhibitors (NRTIs)). Mechanical threshold was tested using von Frey filament fibers. Non-replicating herpes simplex virus (HSV) vectors expressing interleukin 10 (IL10) were inoculated into the hindpaws of rats. The expression of TNFα, SDF1α, and CXCR4 in the lumbar spinal cord and L4/5 dorsal root ganglia (DRG) was examined using western blots. IL-10 expression mediated by the HSV vectors resulted in a significant elevation of mechanical threshold. The anti-allodynic effect of IL-10 expression mediated by the HSV vectors lasted more than 3 weeks. The area under the effect-time curves (AUC) in mechanical threshold in rats inoculated with the HSV vectors expressing IL-10, was increased compared with the control vectors, indicating antinociceptive effect of the IL-10 vectors. The HSV vectors expressing IL-10 also concomitantly reversed the upregulation of p-p38, TNFα, SDF1α, and CXCR4 induced by gp120 in the lumbar spinal dorsal horn and/or the DRG at 2 and/or 4 weeks.

Conclusion: The blocking of the signaling of these proinflammatory molecules is able to reduce HIV-related neuropathic pain, which provide a novel mechanism-based approach to treating HIV-associated neuropathic pain using gene therapy.